Conventionally, it is common that a massive amount of content is transferred at offices and homes among personal computers (PCs), mobile phones, and various AV devices typified by digital still cameras and BD recorders. Usually, transfer of content between AV devices is carried out with the use of a personal area network (PAN) employing wired communications such as the universal serial bus (USB) or with the use of bridge media such as SD memory card. However, use of the USB or SD memory card requires cable connection or insertion/withdrawal of the SD card. Therefore, there is a demand for wireless connection from the standpoint of device usability. For example, wireless USB according to which the physical layers are unwired has already been standardized and its specifications are publically available at the URL listed as Non-Patent Literature 1 below. Regarding bridge media such as SD memory card, products implementing a wireless local area network (LAN) compliant with IEEE 802.11 standards (see Non-Patent Literature 2) are already in use (see Non-Patent Literature 3).
From another standpoint of improved device usability, wireless communications are requested to achieve the speed comparable to wired communications in order to reduce communication latency for users. To meet the request, wireless PAN technologies using 60 GHz millimeter-waves have been standardized as a future replacement for wired PAN applications exceeding 1 Gbps offered by USB 3.0, for example. Specifically speaking, the standardization has been developed by IEEE 802.15.3C and Wireless Gigabit (WiGig) Alliance. Especially, the WiGig Alliance has defined an extended MAC layer that is backward compatible with the existing MAC layer compliant with the IEEE 802.11 standards. The WiGig Alliance is also developing, as an upper layer of the extended MAC layer, the IO-protocol adaptation layer (PAL) specifications for adaptation of IO bus protocols, such as USB and PCI Express. Since the architecture as described above will facilitate wireless connection that uses the existing IO bus protocols, the standardization of high-speed wireless communications is waited in expectation.
As one known technology for network extension by using wireless connection, Patent Literature 1 discloses a technology according to which each wireless node connected to a wired network collects and stores information about other nodes and provides the information to a wireless device being at the other end of the connection. This technology allows the user of the wireless device to search for and access content held in the storage connected to the wired network, without having to be aware of the physical connection. In this way, in wireless connection between a wireless device and a wireless node, the use of protocols adapted for wired networks, such as IO-PAL described above, reduces the overhead of protocol conversion and thus enables high-speed communications.